Implement `-fvk-use-dx-layout` (#4912)

* Implement `-fvk-use-dx-layout`

Fixes: #4126

Changes:
* Added fvk-use-dx-layout
* Modified `HLSLConstantBufferLayoutRulesImpl` for correctness (ex: Array is always 16 byte aligned)
* Added kFXCShaderResourceLayoutRulesFamilyImpl and kFXCConstantBufferLayoutRulesFamilyImpl to handle fvk-use-dx-layout
* Added `ConstantBufferLayoutRules` to manage constant buffer rules
* Added `alignCompositeElementOfNonAggregate`/`alignCompositeElementOfAggregate` to handle forced alignment of composites for ConstantBuffers
* `StructuredBuffer` rules are mostly equal to `scalar` layout, not much was needed to be changed to support this behavior.

* seperate legacy constant buffer and how Slang does constant-buffer normally

* undo an addition

* remove accidental test

* Address review and fix

Address review and remove GLSL support since GLSL requires a seperate legalization (need to linearlize structs like with `legalizeMetalIR` to assign explicit offsets)

* comments

* remove aggregate and non-aggregate logic

We don't need this distinction for the logic

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/spirv/cbuffer-not-dx-layout.slang b/tests/spirv/cbuffer-not-dx-layout.slang
new file mode 100644
index 000000000..27063188d
--- /dev/null
+++ b/tests/spirv/cbuffer-not-dx-layout.slang
@@ -0,0 +1,56 @@
+//TEST:SIMPLE(filecheck=SPIRV): -target spirv -entry computeMain -stage compute
+
+cbuffer Test
+{
+//SPIRV: Offset 0
+    uint v0;
+
+//SPIRV: Offset 16
+    float3 v1;
+
+//SPIRV: Offset 32
+    uint3 v2;
+    
+//SPIRV: Offset 48
+    uint2 v3;
+
+//SPIRV: Offset 56
+    uint2 v4;
+
+//SPIRV: Offset 64
+    uint v5[4];
+
+//SPIRV: Offset 128
+    uint3 v6[2];
+};
+
+RWStructuredBuffer<int> outputBuffer;
+
+__generic<T : IArithmetic, let N : int>
+bool comp(vector<T,N> v1, vector<T,N> v2)
+{
+    for (uint i = 0; i < N; i++)
+        if (v1[i] != v2[i])
+            return false;
+
+    return true;
+}
+
+[shader("compute")]
+[numthreads(16, 16, 1)]
+void computeMain()
+{
+    outputBuffer[0] = (true
+            && v0 == 1
+            && comp(v1, float3( 2, 3, 4))
+            && comp(v2, uint3( 5, 6, 7))
+            && comp(v3, uint2( 8, 9 ))
+            && comp(v4, uint2( 10, 11 ))
+            && v5[0] == 12
+            && v5[1] == 13
+            && v5[2] == 14
+            && v5[3] == 15
+            && comp(v6[0], uint3( 16, 17, 18 ))
+            && comp(v6[1], uint3( 19, 20, 21 ))
+        ) ? 100 : 0;
+}
\ No newline at end of file